The present invention relates generally to a fluid cylinder, and more particularly to an apparatus and method of operating a fluid cylinder of a work machine.
Work machines, such as log loaders, typically include a tilt cylinder (i.e. a fluid cylinder) having a rod and a housing. The rod and housing of the tilt cylinder are respectively attached to a work implement and a stick of the work machine. The tilt cylinder operates to rotate or tilt the work implement relative to the stick during the performance of a work function. For example, an operator of a log loader will typically have to actuate the tilt cylinder so as to rotate the work implement relative to the stick before xe2x80x9cgraspingxe2x80x9d logs with the work implement.
After grasping the logs with the work implement it is desirable to place the tilt cylinder in what is commonly known as the xe2x80x9cfloat modexe2x80x9d. Once in the float mode the rod of the tilt cylinder is substantially free to move inwardly and outwardly relative to the housing. Having the rod being able to freely move inwardly and outwardly relative to the housing allows the work implement to freely rotate or swing relative to the stick when loaded. Allowing the work implement to freely swing when loaded reduces the wear and tear on the work machine, and in particular reduces the wear and tear on a rotate motor of the work machine. Moreover, having the tilt cylinder in the float mode of operation when the work implement is grasping a number of logs facilitates the loading of the logs onto a platform, such as a truck bed.
Heretofore, to place the tilt cylinder in and out of the float mode of operation, a switch located in the cab assembly of the work machine had to be manually actuated by the operator. Manually actuating the switch is inconvenient for the operator. As a result, some operators tend to neglect placing the tilt cylinder in the float mode of operation when the work implement is loaded (i.e. grasping logs). As previously mentioned, not placing the tilt cylinder in the float mode of operation increases the wear and tear on the work machine, thereby increasing the maintenance cost thereof.
What is needed therefore is an apparatus and method of operating a fluid cylinder of a work machine which overcomes one or more of the above-mentioned drawbacks.
In accordance with a first embodiment of the present invention, there is provided an apparatus for operating a fluid cylinder of a work machine. The fluid cylinder (i) has a rod and a housing and (ii) is operable in (1) an extend mode in which the rod is urged outwardly from the housing by fluid being advanced by an operational pressure source and (2) a retract mode in which the rod is urged inwardly into the housing by fluid being advanced by the operational pressure source. The apparatus includes a cylinder actuator operatively coupled to the fluid cylinder. The cylinder actuator is positionable between (i) an extend position in which the fluid cylinder is placed in the extend mode, (ii) a retract position in which the fluid cylinder is placed in the retract mode, and (iii) an isolate position in which the fluid cylinder is isolated from the operational pressure source. The apparatus also includes a sensing arrangement operatively coupled to the cylinder actuator and the fluid cylinder so that (i) the sensing arrangement detects when the cylinder actuator is in the isolate position and (ii) the sensing arrangement generates a signal in response to detecting that the cylinder actuator is in the isolate position so as to cause the fluid cylinder to be placed in a float mode of operation in which the rod is substantially free to move outwardly from the housing or move inwardly into the housing.
In accordance with a second embodiment of the present invention, there is provided a work machine. The work machine includes a work implement and a fluid cylinder mechanically coupled to the work implement. The fluid cylinder (i) has a rod and a housing and (ii) is operable in (1) an extend mode in which the rod is urged outwardly from the housing and (2) a retract mode in which the rod is urged inwardly into the housing. The work machine also includes an operational pressure source for advancing a fluid so as to cause the rod to be urged outwardly or inwardly relative to the housing. The work machine further includes a control valve (i) positionable between an extend position, a retract position, and a neutral position, and (ii) fluidly coupled with the operational pressure source and the fluid cylinder so that when the control valve is (1) in the extend position the fluid cylinder is in the extend mode, (2) in the retract position the fluid cylinder is in the retract mode, and (3) in the neutral mode the fluid cylinder is isolated from the operational pressure source. The work machine also includes a float valve fluidly coupled to the fluid cylinder. The float valve being positionable between (i) an open position in which fluid from the fluid cylinder can be advanced through the float valve and (ii) a closed position in which fluid from the fluid cylinder can not be advanced through the float valve. The work machine also includes a sensing arrangement (i) coupled to the control valve and the float valve and (ii) operable so as to cause the float valve to be (1) positioned in the open position in response to detecting that the control valve is positioned in the neutral position and (2) positioned in the closed position in response to detecting that the control valve is positioned in the extend position or the retract position.
In accordance with a third embodiment of the present invention there is provided a method of operating a fluid cylinder which is operatively coupled to a cylinder actuator, wherein (i) the fluid cylinder has a housing and a rod positioned within the housing and (ii) the cylinder actuator is positionable between (1) an extend position in which the rod is urged outwardly from the housing by fluid being advanced by an operational pressure source, (2) a retract position in which the rod is urged inwardly into the housing by fluid being advanced by the operational pressure source, and (3) an isolate position in which the fluid cylinder is isolated from the operational pressure source. The method includes the steps of (i) detecting when the cylinder actuator is in the isolate position with a sensor and (ii) placing the fluid cylinder in a float mode of operation in which the rod is substantially free to move outwardly from the housing or move inwardly into the housing in response to detecting with the sensor that the cylinder actuator is in the isolate position.